The objective of this research is to develop an advanced non-invasive technique for the optical detection of neonatal jaundice. The principle of the method is that information in the reflectance spectra of the infant's skin which yellows because of excess bilirubin in the body can be correlated in a quantitative manner with the serum total bilirubin level which is an indicator of hyperbilirubinemia. This method could impact infant health care by replacing the subjective visual detection method and eliminate the infection risk present in blood sampling. The method could be suited for mass screening in the nursery and for assessment of phototherapy treatment on jaundiced infants. An extensive set of observations on a sample population of 16 healthy infants is currently being analyzed to evaluate the effect of variables in the procedures. The variables being studied are time of day, location of observation site on the infant, blanched vs. unblanched skin condition, pigmentation (caucasian and blacks), and infant age. Laboratory tests of total and indirect bilirubin, total protein, hematocrit, albumin and globulin are performed concurrently. The scope of the research plan includes three tasks: (1) to obtain and analyze observations on a large sample population of well infants using optimized and evaluated procedures, (2) to design experiments and obtain observations on a small sample population of infants undergoing phototherapy treatment and of sick infants under intensive care, and (3) to develop a model establishing a physical basis for the optical detection method.